Projection optical system, exposure apparatus, and exposure method

Abstract

An immersion projection optical system having, for example, a catadioptric and off-axis structure, reduces the portion of an image space filled with liquid (immersion 5 liquid), The projection optical system, which projects a reduced image of a first plane onto a second plane through the liquid, includes a refractive optical element (Lp) arranged nearest to the second plane. The refractive optical element includes a light emitting surface (Lpb) shaped to be substantially symmetric with respect to two axial directions (XY·axes) perpendicular to each other on the second plane. The light emitting surface has a central axis (Lpba) that substantially coincides with a central axis ( 40 a ) of a circle ( 40 ) corresponding to a circumference of a light entering surface (Lpa) of the refractive optical element. The central axis of the light emitting surface is decentered in one of the two axial directions (Y˜axis) from an optical axis (AX).

What is claimed: 
     
       1. A catadioptric projection optical system which projects a reduced image of an object located on a first plane with light from the object onto a second plane through liquid, the catadioptric projection optical system comprising:
 a concave reflection mirror provided on an optical path of the light from the first plane; and 
 a positive lens provided on the optical path of the light from the concave reflection mirror, the positive lens having a light emitting surface including a light emitting region through which the light passes; 
 wherein the positive lens is provided so that the light emitting surface faces the second plane and contacts the liquid located in at least the optical path between the catadioptric projection optical system and the second plane, and 
 the light emitting surface is one-fold rotationally symmetric with respect to an optical axis of the catadioptric projection optical system. 
 
     
     
       2. The catadioptric projection optical system according to  claim 1 , wherein the light emitting surface is shaped to be substantially symmetric with respect to one of two axial directions perpendicular to each other on the second plane and asymmetric with respect to the other axial direction, and a central axis of the light emitting surface is decentered from the optical axis of the catadioptric projection optical system along the one axial direction. 
     
     
       3. The catadioptric projection optical system according to  claim 2 , wherein the reduced image is projected on a projection region not including the optical axis of the catadioptric projection optical system in the second plane, and a center axis of the projection region substantially coincides with the center axis of the light emitting plane. 
     
     
       4. The catadioptric projection optical system according to  claim 1 , wherein the light emitting surface is shaped to be substantially symmetric with respect to two axial directions perpendicular to each other on the second plane, a center of circle corresponding to outer circumference of an light entering surface of the positive lens substantially coincides with the optical axis of the catadioptric projection optical system, and a center axis of the light emitting surface is decentered from the optical axis of the catadioptric projection optical system along one of the two axial directions perpendicular to each other on the second plane. 
     
     
       5. The catadioptric projection optical system according to  claim 1 , wherein the reduced image is projected on a projection region not including the optical axis of the catadioptric projection optical system in the second plane, and a center of the light emitting surface is arranged at the same side as a position of a center of the projection region with respect to a direction along a straight line passing through the optical axis in the second plane and the center of the projection region. 
     
     
       6. The catadioptric projection optical system according to  claim 5 , wherein the center of the light emitting surface is arranged so as to coincide with the center of the projection region with respect to the direction along the straight line. 
     
     
       7. The catadioptric projection optical system according to  claim 5 , wherein the center of the light emitting surface is arranged so that a position of the center of the light emitting surface with respect to a direction perpendicular to the straight line in the second plane coincides with the optical axis of the catadioptric projection optical system. 
     
     
       8. The catadioptric projection optical system according to  claim 1 , wherein the light emitting surface is provided at position nearer to the second plane than that of a surface different from the light emitting surface in a surface opposing to the second plane. 
     
     
       9. The catadioptric projection optical system according to  claim 1 , further comprising:
 a first imaging optical system which forms a first intermediate image of the object with the light from the object; 
 a second imaging optical system which includes the concave reflective mirror and forms a second intermediate image of the object with the light from the first intermediate image; and 
 a third imaging optical system which includes the positive lens and forms the reduced image with the light from the second intermediate image. 
 
     
     
       10. The catadioptric projection optical system according to  claim 9 , wherein each of the first and third imaging optical systems is dioptric optical system. 
     
     
       11. The catadioptric projection optical system according to  claim 9 , wherein the third imaging optical system comprises an aperture stop, and all of lenses arranged at the second plane side in comparison with the aperture stop are convex lenses of which convex surfaces face to the first plane side. 
     
     
       12. The catadioptric projection optical system according to  claim 11 , wherein the positive lens is a plano-convex lens. 
     
     
       13. An exposure apparatus which exposes a substrate through liquid by light from an object, the exposure apparatus comprising;
 a stage which holds the substrate and is movable; and 
 the catadioptric projection optical system according to  claim 1 , which projects the reduced image of the object through the liquid onto the substrate held by the stage. 
 
     
     
       14. The exposure apparatus according to  claim 13 , further comprising:
 a supply mechanism which supplies the liquid to an optical path of the light from the catadioptric projection optical system; and 
 a discharge mechanism which discharges the liquid supplied by the supply mechanism. 
 
     
     
       15. The exposure apparatus according to  claim 13 , wherein the stage makes the substrate scan with respect to the reduced image projected by the catadioptric projection optical system. 
     
     
       16. A device manufacturing method comprising;
 exposing a substrate by using the exposure apparatus according to  claim 13 ; and 
 developing the substrate that has been exposed by using the exposure apparatus. 
 
     
     
       17. An exposure method of exposing a substrate through liquid with light from an object, comprising:
 holding the substrate by a stage; and 
 projecting a reduced image of the object through liquid by the catadioptric projection optical system according to  claim 1 , onto the substrate held by the stage. 
 
     
     
       18. The exposure method according to  claim 17 , further comprising:
 supplying the liquid to the optical path of the light from the catadioptric projection optical system; and 
 discharging the liquid supplied to the optical path. 
 
     
     
       19. The exposure method according to  claim 17 , further comprising
 making the substrate scan with respect to the reduced image projected by the catadioptric projection optical system. 
 
     
     
       20. A device manufacturing method comprising:
 exposing a substrate by using the exposure method according to  claim 17 ; and 
 developing the substrate that has been exposed by using the exposure method.